Freeze dryers typically incorporate a pressure vessel having a freeze drying chamber for receiving a plurality of containers or vials containing sterile material to be freeze dried. Access to the chamber for automated loading and removal of vials is through a rectangular opening, or slot, formed in a wall or in the main door of the chamber. The slot is closed by a slot door which, with the chamber, forms a vacuum seal around the slot. To enable vials to be inserted into and removed from the chamber, the slot door is vertically raised relative to the slot by moving the slot door along guide tracks.
Maintaining sterile conditions within the dryer requires periodic cleaning and sterilization of the slot door and guide tracks. In order to access the rear surface of the slot door, that is, the surface of the slot door which faces the chamber, it is necessary to manually remove the slot door from the guide tracks, thereby increasing the cost and duration of the cleaning and sterilization.